use std::collections::BTreeSet;

fn char_to_score(c: char) -> u32 {
    match c {
        'a'..='z' => c as u32 - 96,
        'A'..='Z' => c as u32 - 38,
        _ => unreachable!(),
    }
}

pub fn part1(input: &str) -> impl std::fmt::Display {
    input
        .lines()
        .map(|l| l.split_at(l.len() / 2))
        .map(|(l, r)| {
            let a: BTreeSet<char> = l.chars().collect();
            let b: BTreeSet<char> = r.chars().collect();
            a.intersection(&b)
                .next()
                .expect("We know there is at least one")
                .clone()
        })
        .map(char_to_score)
        .sum::<u32>()
}

pub fn part2(input: &str) -> impl std::fmt::Display {
    ""
}

#[test]
fn test_part1() {
    assert_eq!("15", part1("A Y\nB X\nC Z").to_string())
}

#[test]
fn test_part2() {
    assert_eq!("12", part2("A Y\nB X\nC Z").to_string())
}